Cryogen pump

Abstract

A cryogen pump, including: a pump section that includes: a bellow with an inlet opening at a first end and an exit opening, the inlet opening in direct fluid communication with a volume of a cryogen, the exit opening at least in fluid communication with a second end of the bellow opposing the first end, a pair of plugs configured to sealingly close the opposing ends of the bellow, the pair of plugs cooperating so that when one plug sealingly closes one of the ends, the other end of the bellow is open; and a drive section configured to drive the pump section in a reciprocating manner so as to move the plugs.

Description

BACKGROUND[0001]1. Field of the Invention[0002]Embodiments of the present invention relate generally to cryogenic pumps and, more particularly, to submerged or insulated cryogenic pumps.[0003]2. Description of Related Art[0004]Handling cryogen fluid at, or slightly below its boiling temperature, which is well below room temperature, can be cumbersome due to the creation of two-phase Condition with any heat absorbed from the environment. Liquid nitrogen, as a cryogen, has additional handling difficulties associated with the Leidenfrost effect and the 700 fold volume expansion from liquid to gas.[0005]As is conventionally known, liquid nitrogen has characteristics that make it difficult to fill a volume. This difficulty is due to the Lindenfrost effect, by which a cushion of vapor results whenever the liquid comes into contact with a surface with a temperature higher than the boiling temperature.[0006]The change of pressure may be another source of difficulties related to the physical...

AI Technical Summary

Benefits of technology

The present invention provides a method to fill a cylinder or bellow with cryogenic liquid without the need for a suction pump or to lower the pressure in the cylinder. This is done by creating conditions of communicating vessels, such as by gravitational force. Additionally, the invention reduces or eliminates the impact of ambient temperature by vacuum insulating the cylinder or bellow, which eliminates the need to submerge the pumping unit into the cryogenic liquid.

Problems solved by technology

Handling cryogen fluid at, or slightly below its boiling temperature, which is well below room temperature, can be cumbersome due to the creation of two-phase Condition with any heat absorbed from the environment.

Liquid nitrogen, as a cryogen, has additional handling difficulties associated with the Leidenfrost effect and the 700 fold volume expansion from liquid to gas.

As is conventionally known, liquid nitrogen has characteristics that make it difficult to fill a volume.

This difficulty is due to the Lindenfrost effect, by which a cushion of vapor results whenever the liquid comes into contact with a surface with a temperature higher than the boiling temperature.

The change of pressure may be another source of difficulties related to the physical state of the fluid.

First, it makes it difficult to press the fluid since gaseous phase is compressible.

It is very difficult to suck liquid nitrogen.

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